Den has dark eyes and shaggy brown hair parted in the middle. He wears the standard uniform of the Training Corps with a chipped teal shirt underneath.
Den admires the Survey Corps and dreams of one day joining them to defeat the Titans. He enjoys reading jokes from a joke book with his friend, Elin.
StoryIn Shiganshina District in the year 845, Den and Elin run into an alleyway to escape members of the Garrison after stealing some food. The two lose the Garrison members and overhear one of them saying that he would throw them to the Titans if he caught them. The two sit on top of a cellar door and Elin questions why the soldiers would say something so cruel. Den claims that not all soldiers are bad but Elin disagrees saying that even if Den thinks the Survey Corps are heroes, it is still all one army.
As the two are eating their bread the cellar door suddenly collapses and they fall into the cellar. Elin suggests that they leave before the owner can come back but Den tells her that he wants to look around. Den opens a chest, finds a joke book and asks what a joke is. Elin tells him to read the book to find out. Den reads a joke to Elin and the two laugh at it.
As Den continues to read jokes he is interrupted by a loud noise coming from outside. The two leave the cellar and climb the onto the rooftop. From the rooftop, they see a Colossus Titan peering over Wall Maria. The two of them run away to a ship as Titans invade the town. Den tells Elin that if they survive, Den will join the Survey Corps and find a way to kill all the Titans.
The two join the Training Corps and five years after the fall of Wall Maria they stand in Trost District and look upon the town. Elin thanks Den for staying with her over the years and Den comments that the joke book helped them get through dark times. Suddenly a Titan kicks down the gate to Trost District and the two soldiers look behind them to see the Titan staring back at them.
Twenty minutes later, Den attempts to kill the Titan to save Elin but the Titan grabs him with its hand. As the Titan is about to eat him Den tells the Titan one last joke. To his surprise, the Titan drops him and laughs itself to death. Den looks back at the dead Titan and declares that his joke book has become humanity's greatest weapon.